On the changeover, microphones picked up Kyrgios calling the winner "the greatest shot you've ever seen."

(In his post-match press conference, Kyrgios was asked about the shot. "It was unbelievable," he said with a smile. I’m probably going to post it on Instagram.")

Federer spoke about the shot, too, after closing out a 6-4, 6-1, 7-5 win that featured a close first set—Kyrgios had 0-40 in one return game—a blowout second and an entertaining third, which included the winner from six inches off the ground.

"It really only happens on a center court of this size," Federer told ESPN's Darren Cahill about the genesis of the shot. "The funny thing about this shot is, I didn’t think about it until I hit it. I actually didn't think I was going to get it."

But get it he did, and Federer moves on to the fourth round, where he'll face another Aussie, John Millman.

All in Federer's bottomless bag of tricks, right? Well...

"Definitely a bit of luck, good feet," mused Federer, "but I guess I deserve it because I went for it."

Wake up every morning with Tennis Channel Live at the US Open starting at 8 a.m. ET. For three hours leading up to the start of play, Tennis Channel’s team will break down upcoming matches, review tournament storylines, breaking news and player developments.

Tennis Channel’s encore, all-night match coverage will begin every evening at 11 p.m. ET, with the exception of earlier starts on Saturday and Sunday of championship weekend.

Watch the best matches from the first three Grand Slams on Tennis Channel PLUS. From Federer’s historic win at the Australian Open to Halep’s breakthrough at Roland Garros. It all starts Monday, August 27th.

Follow the Race to ATP Finals this fall on Tennis Channel PLUS. Live coverage from the biggest stops including Beijing, Tokyo, Shanghai & Paris.